By FIONA COHEN, SPECIAL TO SEATTLEPI.COM

Published 10:00 pm, Sunday, March 29, 2009

As the waste falls off the truck, it steams and holds its shape, like a thick casserole. But this load of yard and food waste -- branches, ivy, grapefruit peels, dead houseplants, and brown slime -- is just the starting ingredient for what they cook at Cedar Grove Composting.

Fish out the metal and the plastic, grind it up, add some wood chips and a few scoops of finished compost, stack the mixture 12 feet high on a ventilated pad and cover it with waterproof, breathable fabric (made by W.L. Gore & Associates, the makers of Gore-Tex).

Leave it there, and fan it with air when it needs it. Wait eight to 12 weeks (depending on the weather), taking the cover off partway through, and that 140-foot-long, 12-foot-high heap of garbage salad will turn into silky soft, absorbent humus, ready for the garden.

In 2008 Cedar Grove converted more than 100,000 tons of food and yard waste from Seattle households and businesses into garden products. It could do more: food waste makes up one-third of the stuff Seattle residents send to the landfill.

Starting Monday, more of that garbage will end up at Cedar Grove's plants in Everett and Maple Valley. Seattle Public Utilities is changing what it collects. Food and yard-waste pick-up will be every week, and all single-family homes must have it -- so about 30,000 more households have bins. And along with the coffee grounds and vegetable trimmings, people can put in meat, fish, and dairy products.

At the same time, they'll also be able to recycle a wider variety of plastic, paper and metal items.

At first the impact is likely to be modest. Seattle Public Utilities estimates this year's changes will result in about 15,000 more tons -- less than 2 percent of Seattle's waste -- being kept out of the landfill.

Brett Stav, senior planning and development specialists for Seattle Public Utilities said it would take some time for many people to change how they deal with discarded food.

"The whole concept of not throwing it in the garbage for some people is going to be perplexing," he said.

About 48 percent of Seattle's waste is now composted or recycled. Seattle Public Utilities aims to increase that to 60 percent by 2012.

Stav expects that over time, more and more people will send food waste to be composted, and save money by lowering their trash collection.

"It's reasonable to expect that there's going to be a trial period, that 40,000 people will see this new container and experiment with it," Stav said. "Some people have trepidations over rats or smell. They're going to understand that those trepidations are going to go away because the new container is probably better than your garbage can."

Over at Cedar Grove's facility in Everett, six crows watch an excavator construct a new compost heap.

The facility smells like a farm and in a way, that's what it is -- though the produce is dirt, and the livestock is bacteria. When the people at Cedar Grove add a few scoops of finished compost to a heap of food and yard waste, they add with it the bacteria to make composting happen.

As the bacteria break down the organic matter, they give off heat. That's why the compost steams. Under the fabric covers, the temperatures can reach as high as high as 175 degrees -- more than enough to kill off the germs in a stinky fish-head.

In summary

More than half of Seattle households will have a new garbage collection day starting on Monday. If you don't know when yours is, look at your garbage can for a sticker saying the garbage day. If there isn't one, ask a neighbor or call Seattle Public Utilities 206-684-3000.

For more details about the changes to recycling and food and yard waste collection, visit www.seattle.gov/util.